The present invention relates to adhesive transfer devices.
U.S. Pat. No. 5,584,962 discloses a laminating and adhesive transfer apparatus. The apparatus of the ""962 patent has a frame and a pair of nip rollers that rotate in a cooperating relationship by rotating a crank handle actuator. To perform an adhesive transfer operation, a pair of supply rolls are mounted to the apparatus frame and lead end portions of the supply material are unwound from the supply roll and fed in between the nip rollers.
One of the supply materials is a release liner coated with pressure-sensitive adhesive on a surface thereof and the other supply material is a thin plastic film that has an affinity for bonding with the adhesive (referred to in the art as a mask substrate). A selected substrate to which adhesive is to be applied is fed into the nip rollers between the feed materials. Then, the crank handle is rotated so that the nip rollers cooperate to apply pressure to the substrates fed therebetween and to advance the substrates and discharge them outwardly from the machine. As a result, the adhesive on the release liner adheres to both the selected substrate and the portions of the mask extending around the periphery of the selected substrate.
When the substrates are discharged from the machine, they can be severed using a cutter. Then, the mask substrate is peeled back from the release liner to expose the selected substrate. The mask substrate is provided with a relatively high affinity for adhesive bonding so that all the excess adhesive exposed around the periphery of the selected substrate remains bonded thereto and is removed from the release liner during the peeling of the mask substrate. The mask substrate can be thrown away or otherwise discarded. Then, the selected substrate can be peeled back from the release liner and adhered to a contact surface as desired.
The advantage of the device disclosed in the ""962 patent is that it allows for a clean adhesive transfer operation with all the excess adhesive being picked up and taken away by the substrate mask. However, the mask substrate supply roll in the device of the ""962 patent creates some inefficiency that it would be desirable to eliminate. For example, the intermediate step of peeling back the adhesive mask substrate introduces an additional step into the operation.
It is therefore an object of the present invention to provide an adhesive transfer device wherein the use of the adhesive mask is eliminated, but the advantages attained by using the adhesive mask are still retained. To achieve this object, the present invention provides an adhesive transfer device for use with a supply roll carrying a supply of an adhesive carrying substrate for performing an adhesive transfer operation on a selected substrate. The adhesive carrying substrate has a layer of pressure-sensitive adhesive coated on a surface thereof. The device comprises a frame and first and second cooperating structures each having a substrate engaging surface, the first cooperating structure being a nip roller rotatably mounted to the frame. The cooperating structures are mounted to the frame with the substrate engaging surfaces disposed adjacent one another so that the adhesive transfer operation can be initiated by inserting the adhesive carrying substrate and the selected substrate together between the cooperating structures with a first portion of the pressure-sensitive adhesive layer facing the selected substrate and a second portion of the adhesive layer adjacent a periphery of the selected substrate facing the substrate engaging surface of the rotatable nip roller.
The cooperating structures are constructed and arranged such that, after initiating the adhesive transfer operation as aforesaid, the adhesive transfer operation can be continued by advancing the selected substrate and the adhesive carrying substrate between the cooperating structures with the substrate engaging surfaces thereof cooperating to apply pressure to the substrates. This causes the first portion of the pressure-sensitive adhesive layer to adhere to the selected substrate and the second portion of the pressure-sensitive adhesive layer to adhere to a pick-up portion of the substrate engaging surface of the nip roller. The pick-up portion of the substrate engaging surface of the nip roller has a greater affinity for adhesive bonding than the surface of the adhesive carrying substrate on which the layer is coated so that as the substrates are discharged from between the cooperating structures, the second portion of the adhesive layer remains adhered to the pick-up portion of the nip roller rather than to the adhesive carrying substrate.
The device further comprises an adhesive pick-up device that has an adhesive pick-up surface with a greater affinity for adhesive bonding than the pick-up portion of the substrate engaging surface of the nip roller. The adhesive pick-up device is disposed adjacent to the nip roller with the adhesive pick-up surface engaging the substrate engaging surface of the nip roller such that, as the nip roller rotates during the adhesive transfer operation, (a) the pick-up portion of the nip roller having the second portion of the adhesive layer adhered thereto engages the adhesive pick-up surface of the pick-up device with sufficient pressure to cause the second portion of the adhesive to adhere to the pick-up surface so that the second portion of the adhesive layer remains bonded to the adhesive pick-up surface rather than to the substrate engaging surface of the nip roller and (b) the adhesive pick-up device continually advances the adhesive pick-up surface so that the portions of the adhesive pick-up surface with the second portion of the adhesive layer adhered thereto is moved away as the nip roller continues to rotate and is replaced by a portion of the adhesive pick-up surface that is devoid of adhesive.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.